Faculty Bibliography

This article reviews the diagnosis and treatment of flexor tendon injuries of the hand highlighting flexor tendon anatomy, important pre-operative imaging findings, surgical options, and post-operative complications. Imaging plays a key role in guiding treatment of these difficult to manage injuries. Thus, it is important for radiologists to have a sound understanding of factors important in treatment decision-making. In the pre-operative setting, accurately identifying the location of the torn proximal tendon stump in subacute and chronic injuries helps dictate whether the patient is a candidate for a primary flexor tendon repair or may require a tendon reconstruction to restore function. In the post-operative setting, the status of the repair and presence of surrounding adhesions help dictate if and when the patient will require subsequent surgery and whether that surgery will be a tenolysis, revision repair, reconstruction, or fusion.

Pronator syndrome is a median nerve entrapment neuropathy that can be difficult to diagnose due to its variable presentation and objective findings. Neurolymphomatosis is an uncommon disease in which malignant lymphocytes infiltrate central or peripheral nerve endoneurium and is often missed for prolonged periods prior to diagnosis. We present a rare case of pronator syndrome and anterior interosseous nerve palsy due to neurolymphomatosis that was occult on initial MRI in spite of the presence of a median nerve mass discovered intra-operatively during neurolysis. This case demonstrates the value of ultrasound for the examination of peripheral nerve pathology and illustrates its utility as an adjunct to MRI, in part due to the ability to screen a large region.

BACKGROUND:Wrist pain in the extended or extended weightbearing positions may be incompletely evaluated using standard magnetic resonance imaging (MRI) with standard rigid clamshell coils in the neutral position. PURPOSE/OBJECTIVE:To evaluate a flexible 24-channel glove coil and harness when imaging the wrist in neutral, dorsally extended, and weightbearing positions. MATERIAL AND METHODS/METHODS:Ten wrists in 10 asymptomatic volunteers (mean age = 29 years) were scanned. Participants underwent 3-T MRI using the harness and flexible glove coil, acquiring sagittal turbo spin echo (TSE) and half-Fourier acquisition single-shot turbo spin echo (HASTE) pulse sequences. Static TSE images were obtained in neutral, extended, and weightbearing positions using proton density parameters and independently evaluated by two radiologists for: dorsal radiocarpal ligament thickness; radiocapitate, radiolunate, and capitatolunate angles; palmar translation of the lunate on the radius; angulation of the extensor tendons; and distance from the distal extensor retinaculum to Lister's tubercle. Cine HASTE images were dynamically acquired between neutral-maximum extension to measure the radiocapitate angle. RESULTS: < 0.01). CONCLUSION/CONCLUSIONS:Significant increases in dorsal radiocarpal ligament thickness, articular and tendon angulations occur during wrist extension, that further increase with dorsal weightbearing.

Injuries are common in competitive baseball players and can occur in all facets of the game. The majority of the existing literature on injuries in baseball players has focused on injuries secondary to the overhead throw with very little attention given to injuries sustained while batting. The baseball swing is a complex, often violent, motion that predisposes batters to a variety of injuries affecting the spine, trunk, pelvis, and extremities. Knowledge of injury patterns that commonly occur during the baseball swing and radiologic findings important to the treating physician can help radiologists provide accurate imaging interpretations that appropriately guide patient management.

Elbow pain is very common and can be due to many pathologic conditions. After radiographs are obtained, advanced imaging is often necessary. Both ultrasonography and MR imaging can be used to evaluate the many important soft-tissue structures of the elbow, with each modality having advantages and disadvantages in certain clinical scenarios. Imaging findings between the two modalities often correlate. It is important for musculoskeletal radiologists to understand normal elbow anatomy and how best to use ultrasonography and MR imaging to evaluate elbow pain. In this way, radiologists can provide expert guidance to referring clinicians and best guide patient management.

OBJECTIVE:To determine if MR neurography of the common peroneal nerve (CPN) predicts a residual motor deficit at 12-month clinical follow-up in patients presenting with foot drop. MATERIALS AND METHODS/METHODS:A retrospective search for MR neurography cases evaluating the CPN at the knee was performed. Patients were included if they had electrodiagnostic testing (EDX) within 3 months of imaging, ankle and/or forefoot dorsiflexion weakness at presentation, and at least 12-month follow-up. Two radiologists individually evaluated nerve size (enlarged/normal), nerve signal (T2 hyperintense/normal), muscle signal (T2 hyperintense/normal), muscle bulk (normal/Goutallier 1/Goutallier > 1), and nerve and muscle enhancement. Discrepancies were resolved via consensus review. Multivariable logistical regression was used to evaluate for association between each imaging finding and a residual motor deficit at 12-month follow-up. RESULTS:Twenty-three 3 T MRIs in 22 patients (1 bilateral, mean age 52 years, 16 male) met inclusion criteria. Eighteen cases demonstrated common peroneal neuropathy on EDX, and median duration of symptoms was 5 months. Six cases demonstrated a residual motor deficit at 12-month follow-up. Fourteen cases underwent CPN decompression (1 bilateral) within 1 year of presentation. Three cases demonstrated Goutallier > 1 anterior compartment muscle bulk. Multivariable logistical regression did not show a statistically significant association between any of the imaging findings and a residual motor deficit at 12-month follow-up. CONCLUSION/CONCLUSIONS:MR neurography did not predict a residual motor deficit at 12-month follow-up in patients presenting with foot drop, though few patients demonstrated muscle atrophy in this study.

Neuropathic symptoms involving the wrist are a common clinical presentation that can be due to a variety of causes. Imaging plays a key role in differentiating distal nerve lesions in the wrist from more proximal nerve abnormalities such as a cervical radiculopathy or brachial plexopathy. Imaging complements electrodiagnostic testing by helping define the specific lesion site and by providing anatomical information to guide surgical planning. This article reviews nerve anatomy, normal and abnormal findings on ultrasonography and magnetic resonance imaging, and common and uncommon causes of neuropathy.

OBJECTIVE:To evaluate the effect of intravenous (IV) contrast on sensitivity, specificity, and accuracy of magnetic resonance (MR) neurography of the knee with attention to the common peroneal nerve (CPN) in identifying nerve lesions and active muscle denervation changes. MATERIALS AND METHODS/METHODS:A retrospective search for contrast-enhanced MR neurography cases evaluating the CPN at the knee was performed. Patients with electrodiagnostic testing (EDX) within 3 months of imaging were included and those with relevant prior surgery were excluded. Two radiologists independently reviewed non-contrast sequences and then 4 weeks later evaluated non-contrast and contrast sequences. McNemar's tests were performed to detect a difference between non-contrast only and combined non-contrast and contrast sequences in identifying nerve lesions and active muscle denervation changes using EDX as the reference standard. RESULTS:Forty-four exams in 42 patients (2 bilateral) were included. Twenty-eight cases had common peroneal neuropathy and 29, 21, and 9 cases had active denervation changes in the anterior, lateral, and posterior compartment/proximal muscles respectively on EDX. Sensitivity, specificity, and accuracy of non-contrast versus combined non-contrast and contrast sequences for common peroneal neuropathy were 50.0%, 56.2%, and 52.3% versus 50.0%, 56.2%, and 52.3% for reader 1 and 57.1%, 50.0%, and 54.5% versus 64.3%, 56.2%, and 61.4% for reader 2. Sensitivity, specificity, and accuracy of non-contrast and combined non-contrast and contrast sequences in identifying active denervation changes for anterior, lateral, and posterior compartment muscles were not significantly different. McNemar's tests were all negative. CONCLUSION/CONCLUSIONS:IV contrast does not improve the ability of MR neurography to detect CPN lesions or active muscle denervation changes.

Chest, abdominal, and groin pain are common patient complaints that can be due to a variety of causes. Once potentially life-threatening visceral causes of pain are excluded, the evaluation should include musculoskeletal sources of pain from the body wall and core muscles. Percutaneous musculoskeletal procedures play a key role in evaluating and managing pain, although most radiologists may be unfamiliar with applications for the body wall and core muscles. US is ideally suited to guide these less commonly performed procedures owing to its low cost, portability, lack of ionizing radiation, and real-time visualization of superficial soft-tissue anatomy. US provides the operator with added confidence that the needle will be placed at the intended location and will not penetrate visceral or vascular structures. The authors review both common and uncommon US-guided procedures targeting various portions of the chest wall, abdominal wall, and core muscles with the hope of familiarizing radiologists with these techniques. Procedures include anesthetic and corticosteroid injection as well as platelet-rich plasma injection to promote tendon healing. Specific anatomic structures discussed include the sternoclavicular joint, costochondral joint, interchondral joint, intercostal nerve, scapulothoracic bursa, anterior abdominal cutaneous nerve, ilioinguinal nerve, iliohypogastric nerve, genitofemoral nerve, pubic symphysis, common aponeurotic plate, and adductor tendon origin. Relevant US anatomy is depicted with MRI correlation, and steps to performing successful safe US-guided injections are discussed. Confidence in performing these procedures will allow radiologists to continue to play an important role in diagnosis and management of many musculoskeletal pathologic conditions. ^©RSNA, 2021.